Finding Distance from the Origin Given Velocity Graph

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Homework Help Overview

The problem involves determining the distance of a rocket-powered hockey puck from the origin after 4 seconds, based on its velocity components represented in graphs. The subject area pertains to kinematics and the interpretation of velocity-time graphs.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to calculate the distance by finding the area under the velocity graphs for both x and y components. Some participants question the accuracy of the calculations and suggest checking for rounding and significant figures.

Discussion Status

The discussion has explored potential errors in the original poster's calculations, particularly regarding significant figures and rounding. There appears to be a productive direction as participants provide feedback on the method used and the importance of proper formatting for the answer.

Contextual Notes

Participants note the requirement for the answer to be expressed in two significant figures, which may have contributed to the initial confusion regarding the correctness of the solution.

pocketofcandy
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Homework Statement


A rocket-powered hockey puck move along a horizontal friction-less table. The figure (link posted below) shows the graphs of vx and vy, the x- and y- components of the puck's velocity. The puck starts at the origin. How far from the origin is the puck at 4 seconds?

Here is the picture of the two graphs: https://session.masteringphysics.com/problemAsset/1384028/7/4-9.jpg

[moderator's edit: Here's an inserted copy of the image just in case the link evaporates some day]
upload_2016-9-18_14-15-13.png

Homework Equations


area of a triangle: 1/2(b)(h)
area of a square: (l)(w)
sqrt(x2+y2)

The Attempt at a Solution


It appears on the on the vx graph that the velocity increases by an increment of 8 cm every second. (It is confirmed to be at 40 cm at 5 seconds). So I thought the way to do this would be to find the area under both graphs from 0 to 4 seconds.
On the vx graph, I found the area to be 1/2*4*32 = 64 cm. On the vy graph, I found the area to be 30*4 = 120 cm. Then I tried to use the formula for distance to solve and came out with:
sqrt(642 + 1202) = 136 cm.

However, whenever I put this answer in, it says it is incorrect. I guess I'm not really the best at physics, so I'm wondering where it was I made the error? I appreciate any help.
 
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Strange as your answer seems to be correct at least from my judgement
I suppose make sure your answer is rounded correctly and that if required your answer is inputted with the correct units
Other than that I do not see an issue with your method
Maybe significant figures or something?
 
Oh I see now that the site wants the answer to two significant figures. So that would be 1.4 meters then?
 
pocketofcandy said:
Oh I see now that the site wants the answer to two significant figures. So that would be 1.4 meters then?
I believe so
 
It worked that time. Thank you!
 

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